// Tencent is pleased to support the open source community by making ncnn available.
//
// Copyright (C) 2021 THL A29 Limited, a Tencent company. All rights reserved.
//
// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// https://opensource.org/licenses/BSD-3-Clause
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

static void convolution_pack8_int8_neon(const Mat& bottom_blob, Mat& top_blob, const Mat& weight_data_int8, int kernel_w, int kernel_h, int dilation_w, int dilation_h, int stride_w, int stride_h, const Option& opt)
{
    int w = bottom_blob.w;
    int channels = bottom_blob.c;

    int outw = top_blob.w;
    int outh = top_blob.h;
    int outch = top_blob.c;

    const int maxk = kernel_w * kernel_h;

    // kernel offsets
    std::vector<int> _space_ofs(maxk);
    int* space_ofs = &_space_ofs[0];
    {
        int p1 = 0;
        int p2 = 0;
        int gap = w * dilation_h - kernel_w * dilation_w;
        for (int i = 0; i < kernel_h; i++)
        {
            for (int j = 0; j < kernel_w; j++)
            {
                space_ofs[p1] = p2;
                p1++;
                p2 += dilation_w;
            }
            p2 += gap;
        }
    }

    // num_output
    #pragma omp parallel for num_threads(opt.num_threads)
    for (int p = 0; p < outch; p++)
    {
        int* outptr = top_blob.channel(p);

        for (int i = 0; i < outh; i++)
        {
            for (int j = 0; j < outw; j++)
            {
                __m128i _sum0 = _mm_setzero_si128();
                __m128i _sum1 = _mm_setzero_si128();

                const signed char* kptr = weight_data_int8.channel(p);

                // channels
                for (int q = 0; q < channels; q++)
                {
                    const Mat m = bottom_blob.channel(q);
                    const signed char* sptr = m.row<signed char>(i * stride_h) + j * stride_w * 8;

                    for (int k = 0; k < maxk; k++)
                    {
                        __m128i _val0 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8]);
                        __m128i _val1 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8 + 1]);
                        __m128i _val2 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8 + 2]);
                        __m128i _val3 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8 + 3]);
                        __m128i _val4 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8 + 4]);
                        __m128i _val5 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8 + 5]);
                        __m128i _val6 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8 + 6]);
                        __m128i _val7 = _mm_set1_epi16((short)sptr[space_ofs[k] * 8 + 7]);

                        // TODO use _mm_cvtepi8_epi16 on sse4.1
                        __m128i _w0 = _mm_loadl_epi64((const __m128i*)kptr);
                        _w0 = _mm_unpacklo_epi8(_w0, _mm_cmpgt_epi8(_mm_setzero_si128(), _w0));

                        __m128i _sl = _mm_mullo_epi16(_val0, _w0);
                        __m128i _sh = _mm_mulhi_epi16(_val0, _w0);
                        __m128i _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        __m128i _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        __m128i _w1 = _mm_loadl_epi64((const __m128i*)(kptr + 8));
                        _w1 = _mm_unpacklo_epi8(_w1, _mm_cmpgt_epi8(_mm_setzero_si128(), _w1));

                        _sl = _mm_mullo_epi16(_val1, _w1);
                        _sh = _mm_mulhi_epi16(_val1, _w1);
                        _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        __m128i _w2 = _mm_loadl_epi64((const __m128i*)(kptr + 16));
                        _w2 = _mm_unpacklo_epi8(_w2, _mm_cmpgt_epi8(_mm_setzero_si128(), _w2));

                        _sl = _mm_mullo_epi16(_val2, _w2);
                        _sh = _mm_mulhi_epi16(_val2, _w2);
                        _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        __m128i _w3 = _mm_loadl_epi64((const __m128i*)(kptr + 24));
                        _w3 = _mm_unpacklo_epi8(_w3, _mm_cmpgt_epi8(_mm_setzero_si128(), _w3));

                        _sl = _mm_mullo_epi16(_val3, _w3);
                        _sh = _mm_mulhi_epi16(_val3, _w3);
                        _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        __m128i _w4 = _mm_loadl_epi64((const __m128i*)(kptr + 32));
                        _w4 = _mm_unpacklo_epi8(_w4, _mm_cmpgt_epi8(_mm_setzero_si128(), _w4));

                        _sl = _mm_mullo_epi16(_val4, _w4);
                        _sh = _mm_mulhi_epi16(_val4, _w4);
                        _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        __m128i _w5 = _mm_loadl_epi64((const __m128i*)(kptr + 40));
                        _w5 = _mm_unpacklo_epi8(_w5, _mm_cmpgt_epi8(_mm_setzero_si128(), _w5));

                        _sl = _mm_mullo_epi16(_val5, _w5);
                        _sh = _mm_mulhi_epi16(_val5, _w5);
                        _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        __m128i _w6 = _mm_loadl_epi64((const __m128i*)(kptr + 48));
                        _w6 = _mm_unpacklo_epi8(_w6, _mm_cmpgt_epi8(_mm_setzero_si128(), _w6));

                        _sl = _mm_mullo_epi16(_val6, _w6);
                        _sh = _mm_mulhi_epi16(_val6, _w6);
                        _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        __m128i _w7 = _mm_loadl_epi64((const __m128i*)(kptr + 56));
                        _w7 = _mm_unpacklo_epi8(_w7, _mm_cmpgt_epi8(_mm_setzero_si128(), _w7));

                        _sl = _mm_mullo_epi16(_val7, _w7);
                        _sh = _mm_mulhi_epi16(_val7, _w7);
                        _s0 = _mm_unpacklo_epi16(_sl, _sh);
                        _s1 = _mm_unpackhi_epi16(_sl, _sh);

                        _sum0 = _mm_add_epi32(_sum0, _s0);
                        _sum1 = _mm_add_epi32(_sum1, _s1);

                        kptr += 64;
                    }
                }

                _mm_storeu_si128((__m128i*)(outptr + j * 8), _sum0);
                _mm_storeu_si128((__m128i*)(outptr + j * 8 + 4), _sum1);
            }

            outptr += outw * 8;
        }
    }
}
